I’ve been on Lantus / Novorapid for about 8 years now (I’m 30 and have been diabetic for 29 of those.) In the early days of Lantus I had no problems whatsoever, then I hit a similar sort of problem. Huge ass hypos in the night, then soaring sugars before tea.
After a chat with a nurse I split the Lantus into two shots. I now take 18U mid morning and 12U before bed. Removed the hypos and smoothed the curve out (guessing Lantus doesn’t last 24 hours in my case either.)
Just my 2p 